Shingled magnetic recording (SMR) is a technique that increases the capacity of hard-disk drives (HDDs). In contrast to traditional magnetic recording, in which cylinders are written in a non-overlapping manner, SMR groups together a block of N adjacent tracks (referred to as a “shingle”), which are written in-order (i.e., track 0, track 1, . . . , track N−1) with a decreased track spacing. As a result, each subsequent track is written close enough to the previously written track such that it will overlap a portion of it. Once a shingle is completely written, tracks within the shingle cannot be modified without re-writing the entire shingle. This approach may be used to increase the number of tracks that may be written to the disk.
However, squeezing the number of tracks written to a disk does not come without some tradeoffs. As tracks are squeezed closer together, reading back a track within a shingle is made difficult because the read-head will, in addition to sensing the magnetic field of the desired track, also sense the magnetic-field due to adjacent tracks. This phenomenon, known as inter-track interference (ITI), becomes a dominant contributor of noise as the track density is increased. It would be desirable to cancel ITI from one or more adjacent tracks in a shingle to improve the overall signal quality.